\documentclass{standalone}
	
\usepackage[siunitx]{circuitikz}

\begin{document}

\begin{circuitikz}[scale=1.5, transform shape]
\draw (0,0) node[anchor=south] {$n1$};
\draw (0,0) to [Do=D, i>_=i, o-o] (3,0);
\draw (3,0) node[anchor=south] {$n2$};
\end{circuitikz} 

\end{document}
